<html>
  <body style="height:5000px">
    <p>A (mostly) empty page.</p>
  </body>
  <script>
    var gotHide = false;
    var gotOrientationChange = false;
    async function doRequestFullscreen() {
        return document.documentElement.requestFullscreen();
    }
    async function toggleFullscreen() {
      if (!document.fullscreenElement) {
          await doRequestFullscreen();
          await screen.orientation.lock("landscape");
      } else {
        document.exitFullscreen();
      }
    }
    document.addEventListener("visibilitychange", function() {
      if (document.visibilityState !== 'visible') {
        gotHide = true;
      }
    });
    window.addEventListener("orientationchange", function() {
      gotOrientationChange = true;
    });
    document.addEventListener('touchend', function(e) { toggleFullscreen(); }, false);
  </script>
</html>
